Sam Elias called it “a game changer.”

Daniel Woods said it was “the secret to success.”

Still, I was hesitant to try Antihydral—an extreme skin-drying agent from Germany that is used for overly sweaty hands (and feet). I seemed to be doing just fine with regular chalk, and the occasional dab of liquid chalk.

Having good “climbing skin” is as important to us climbers as having good tires are to NASCAR drivers—the point of contact needed for high performance. Just like a V12 turbo engine won’t win the race if the car has a flat tire, having big forearms won’t help you climb if you can’t grab the rock because you have a flapper. Skin, particularly that of the fingertips, that doesn’t hurt too much, tear too easily or sweat too profusely is the most important factor needed for climbing at your limit—and also the one that seems to be least in our control.

When it comes to getting and maintaining good climbing skin, there are two schools of thought: Some believe dry, callused skin is stronger and better for climbing. Others find dry, callused skin to more easily rip (because it’s dry and brittle), and so moisturized skin is better. In truth, good climbing skin is somewhere between the two. Good climbing skin resides in the borderlands between dry, hard, callused skin (which can easily tear) and soft, well-moisturized skin (which flakes away and is generally more painful to climb on).

This spring, I spent three weeks climbing in Spain and I was very pleased by how well my skin held up during my trip. It could always go either way, right? I’ve been on trips where, by the end of it, every single one of my digits is taped up and bleeding. But in Spain, for some reason, everything held up well. No nagging flappers or ruddy splits. I attributed this success to a jar of Joshua Tree Healing Salve that I had been applying at the end of every climbing day. The Healing Salve has 10 organic ingredients, including moisturizers, inflammation reducers, anti-bacterial and antiseptic agents, and skin-cell regenerators. I’d rub a generous daub into my hands right after climbing, and within 10 minutes, the grease would soak into my skin, and it would help relieve a lot of the pain and inflammation I felt from cranking all day. And the next day, my skin felt ready to go again.

I returned from Spain to a lingering wet winter/spring that kept me from climbing for almost a month! During that period, all my calluses began to soften and peel, and every time I did try to climb, my skin would tear and rip. It was awful.

This weak skin persisted even into the summer. Fed up, I remembered Sam’s recommendation of Antihydral. Desperate for a solution, I coughed up $30 and ordered Antihydral, whose main ingredient is Methenamin, from a Foosball website—the only place online I found in the U.S. that sells it.

You apply a very small amount of Antihydral to your hands before going to bed, either the night before a climbing day, or over a series of two or three nights beforehand. The solution leaves a white residue; wash it off the next morning. Two or three treatments of Antihydral will leave your skin feeling drier and harder for days.

Apparently, you’re not supposed to use it if you’re allergic to formaldehyde. (Random!)

After a couple of weeks of testing, I’ve found that my skin has held up really well. Chalk stays on my hands better than ever (I never look down while climbing and see the dreaded wet palm), and grabbing razor blades is noticeably less painful. My skin feels harder, and seeps with sweat less.

Words of advice: Using this stuff is all about maintaining a very fine balance. When I feel my hands getting too dry, I use lotion.

Don’t go nuts with the Antihydral! Be extremely conservative with its application, and monitor how dry your skin is getting. Too frequent applications will make your skin glassy and eventually result in deeply split fingers. Also, I only apply Antihydral to my palms and to the tips of my fingers, taking care not to get the stuff into the creases of my finger joints (where flappers and cracks are most likely to appear). Applications two nights a week seem to work for me, but everyone will be different.

Like Sam and Daniel said, this stuff has been a game changer by helping me keep my largest organ in better nick.